Gavin Macauley

Project Title: Magnetism with a twist – chiral helimagnets

Your current phone is faster than the one you had last. The next one you buy will be yet faster still. We seem to take it for granted that technology gets better, quicker, smaller and more powerful each year. But can this continue? Soon, transistors — the switches inside computers — will reach the size of atoms. The promise of nanotechnology — what Richard Feynman called ‘plenty of room at the bottom’ — will be spent.

My research looks at a solution involving a quantum property of particles: their spin. In particular, I spend my time playing with a new class of materials called Artificial Spin Ices. These are arrays of tiny magnetic islands; in essence, nano-scale Lego. With dimensions on the order of a billionth of a metre, these structures cannot be seen with ordinary microscopes. Instead, I shine electrons onto them to probe their behaviour. What makes Artificial Spin Ice so interesting is that the islands — the spins — talk to each other. Unexpected behaviour then emerges from even the simplest of systems; behaviour that would have been impossible to predict from examining a single magnetic island. I look at ways to use this to probe aspects of fundamental physics. With that, we can help design the next generation of devices, based not on pushing electrons around circuits, but on controlling spin.

The physicist, P. W. Anderson, wrote that “more is different” when it comes to science. If Artificial Spin Ice is anything to go by, “more” — in the form of collections of tiny magnets — might just save technology as well!